KR102546309B1 - Image Quality Compensation Device And Method Of Display Device - Google Patents

Abstract

An apparatus for compensating a picture quality of a display device according to an embodiment of the present specification is provided. The picture quality compensating device of this display device includes a display panel including an OLED for each pixel; an optical compensation unit that sets a PWM (Pulse Width Modulation) duty for controlling OLED emission timing according to luminance and sets a gamma curve to correlate with the PWM duty; a luminance measurement unit acquiring a luminance profile by capturing an image reproduced from the display panel based on the PWM duty and the gamma curve; a data correction unit that analyzes the luminance profile, derives a compensation coefficient for improving luminance deviation, and corrects image data based on the compensation coefficient; and a panel driver writing the corrected image data on the display panel.

Description

Image Quality Compensation Device And Method Of Display Device

The present specification relates to an apparatus and method for compensating a picture quality of a display device.

Various display devices are being developed and released. Among them, the electroluminescent display device is roughly divided into an inorganic light emitting display device and an organic light emitting display device according to the material of the light emitting layer. In particular, an active matrix type organic light emitting display device includes an organic light emitting diode (hereinafter referred to as "OLED") that emits light by itself, and has a fast response speed, luminous efficiency, luminance, and viewing angle. This has great advantages.

An organic light emitting display device arranges pixels each including an OLED in a matrix form, and adjusts luminance of the pixels according to gray levels of image data. Each of the pixels includes a driving TFT (Thin Film Transistor) for controlling the driving current flowing through the OLED according to the gate-source voltage, and one or more switch TFTs for programming the gate-sort voltage of the driving TFT. The display gray level (luminance) is controlled by the amount of light emitted by the OLED that is proportional to .

In such an organic light emitting display device, display defects (display stains) may appear due to various causes. Display unevenness may be caused by process variation or driving characteristics.

Display stains due to process variation are due to the difference in exposure amount in the photolithography process, such as the overlapping area between the gate and drain of the TFT, the height of the spacer, the parasitic capacitance between signal wires, and the parasitic capacitance between signal wires and pixel electrodes. It can be attributed to the fact that it is different from the side. Depending on the cause of the display stain, it may have a standard shape such as a dot, line, band, circle, polygon, etc., or an irregular shape.

On the other hand, display unevenness due to driving characteristics may be caused by unstable changes in luminance at a low OLED driving voltage. Display unevenness due to driving characteristics may be particularly problematic when expressing a low grayscale.

The area where the display stain appears has different luminance and color compared to the normal display surface. Various compensation schemes have been proposed to improve display stains, but it is difficult to implement optimal compensation performance with existing compensation schemes.

Accordingly, the present specification provides an apparatus and method for compensating a picture quality of a display device capable of exhibiting optimal compensation performance in improving display unevenness.

The tasks of the present specification are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

An apparatus for compensating a picture quality of a display device according to an embodiment of the present specification is provided. The picture quality compensating device of this display device includes a display panel including an OLED for each pixel; an optical compensation unit that sets a PWM (Pulse Width Modulation) duty for controlling OLED emission timing according to luminance and sets a gamma curve to correlate with the PWM duty; a luminance measurement unit acquiring a luminance profile by capturing an image reproduced from the display panel based on the PWM duty and the gamma curve; a data correction unit that analyzes the luminance profile, derives a compensation coefficient for improving luminance deviation, and corrects image data based on the compensation coefficient; and a panel driver writing the corrected image data on the display panel.

A method for compensating a picture quality of a display device according to an embodiment of the present specification is provided. The method for compensating the image quality of the display device includes an optical compensation step of setting a Pulse Width Modulation (PWM) duty for controlling OLED emission timing according to luminance and setting a gamma curve to correlate with the PWM duty; a luminance measurement step of obtaining a luminance profile by capturing a reproduced image based on the PWM duty and the gamma curve in the display panel; a data correction step of deriving a compensation coefficient for improving luminance deviation by analyzing the luminance profile, and correcting image data based on the compensation coefficient; and a panel driving step of writing the corrected image data on the display panel.

Details of other embodiments are included in the detailed description and drawings.

Embodiments of the present specification fix the white data voltage in the luminance region where camera compensation is performed to improve display unevenness and express luminance only with PWM dimming, thereby maintaining the same camera compensation performance at various luminances, thereby providing optimal compensation. performance can be achieved.

Effects according to the embodiments of the present specification are not limited to those exemplified above, and more diverse effects are included in the present specification.

1 is a block diagram showing an apparatus for compensating a picture quality of a display device according to an embodiment of the present specification.
2 is a diagram showing a pixel array according to an embodiment of the present specification.
3 is a diagram showing one pixel circuit according to an exemplary embodiment of the present specification.
4 is a diagram showing a method of controlling PWM duty according to an embodiment of the present specification.
5 is a diagram showing a gamma curve correlated with a PWM duty for each luminance region according to an embodiment of the present specification.
6 is a diagram showing a camera compensation scheme according to an embodiment of the present specification.
7 is a diagram illustrating a method for compensating a picture quality of a display device according to an embodiment of the present specification.
8 is a diagram for explaining that compensation performance is improved when a method for compensating a picture quality of a display device according to an embodiment of the present specification is applied.

Advantages and features of this specification, and methods of achieving them, will become clear with reference to embodiments described below in detail in conjunction with the accompanying drawings. However, this specification is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments make the disclosure of this specification complete, and common knowledge in the art to which this specification belongs. It is provided to completely inform the person who has the scope of the invention, and this specification is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of this specification are illustrative, so this specification is not limited to the matters shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present specification, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present specification, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, when the positional relationship of two parts is described as 'on ~', 'upon ~', '~ below', 'next to', etc., 'right' Or, unless 'directly' is used, one or more other parts may be located between the two parts.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present specification.

Like reference numbers designate like elements throughout the specification.

Each feature of the various embodiments of the present specification can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or together in a related relationship. may be

Hereinafter, various embodiments of the present specification will be described in detail with reference to the accompanying drawings. The component names used in the following description are selected in consideration of the ease of writing the specification, and may be different from the actual product part names.

1 is a block diagram showing an apparatus for compensating a picture quality of a display device according to an embodiment of the present specification. 2 is a diagram showing a pixel array according to an embodiment of the present specification. And, FIG. 3 is a diagram showing one pixel circuit according to an embodiment of the present specification.

A display device according to an embodiment of the present specification is based on an electroluminescent display device. The electroluminescent display device includes an inorganic light emitting display device and an organic light emitting display device. In the embodiments of the present specification, the organic light emitting display device will be mainly described. However, the technical concept of the present specification may be applied to an organic light emitting display device as well as an inorganic light emitting display device.

Referring to FIG. 1 , an apparatus for compensating for a picture quality of a display device according to an embodiment of the present specification includes a display panel 10 having pixels PXL and a panel driving unit 12 that drives signal lines connected to the pixels PXL. , 13), and a timing controller 11 controlling the panel driving units 12 and 13.

A plurality of data lines 14 and a plurality of gate lines 15 cross each other on the display panel 10 , and the pixels PXL are arranged in a matrix form to form a pixel array as shown in FIG. 2 .

Referring to FIG. 2 , the pixel array includes a plurality of horizontal pixel lines L1 to L4, and horizontally adjacent to each other on the horizontal pixel lines L1 to L4, and each gate line 15a(1) to 15a(4). ), and a plurality of pixels PXL connected in common to 15b(1) to 15b(4)) are disposed. Here, each of the horizontal pixel lines L1 to L4 is not a physical signal line, but refers to a pixel set corresponding to one line implemented by horizontally neighboring pixels PXL. The pixel array includes first power lines 17 for supplying the high-potential power supply voltage EVDD to the pixels PXL, and second power lines 16 for supplying the reference voltage Vref to the pixels PXL. this may be included. Also, the pixels PXL may be further connected to the low potential power supply voltage EVSS.

Each of the pixels PXL includes an OLED and a driving TFT DT as shown in FIG. 3 , and may further include a first switch TFT ST1 and a second switch TFT ST2 and a storage capacitor Cst. , but not limited thereto. Various variations of the pixel circuit are possible.

Referring to FIG. 3 , an OLED is a self-luminous device that emits light according to a driving current. The OLED includes an anode electrode connected to the source electrode of the driving TFT (DT) through the second node N2, a cathode electrode connected to the low potential power supply voltage EVSS, and an organic compound layer provided between the anode electrode and the cathode electrode. includes The organic compound layer is a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer (electron injection layer, EIL). When a power supply voltage is applied to the anode electrode and the cathode electrode, holes that have passed through the hole transport layer (HTL) and electrons that have passed through the electron transport layer (ETL) move to the light emitting layer (EML) to form excitons, and as a result, the light emitting layer (EML) visible light is generated.

Referring to FIG. 3 , the driving TFT (DT) is a driving element that adjusts the driving current according to the gate-source voltage (Vgs). The gate electrode of the driving TFT (DT) is connected to the first node N1, and the source electrode is connected to the second node N2. A reference voltage Vref may be applied to the source electrode of the driving TFT DT through the second power supply line 16 . Further, the high potential driving voltage EVDD may be applied to the drain electrode of the driving TFT DT through the first power line 17 and the second switch TFT ST2.

Referring to FIG. 3 , the first switch TFT ST1 is turned on/off according to the scan signal SCAN to control current flow between the data line 14 and the first node N1. The first switch TFT (ST1) is turned on according to the scan signal (SCAN) and applies the data voltage (Vdata) to the gate electrode of the driving TFT (DT). The first switch TFT (ST1) has a gate electrode connected to the first gate line 15a, a drain electrode connected to the data line 14, and a source electrode connected to the first node N1.

Referring to FIG. 3, the second switch TFT (ST2) is turned on/off according to the emission signal (EM) to control the flow of current between the first power line 17 and the drain electrode of the driving TFT (DT). The second switch TFT (ST2) is turned on according to the emission signal (EM) and applies the high-potential power supply voltage (EVDD) to the drain electrode of the driving TFT (DT). The second switch TFT (ST2) has a gate electrode connected to the second gate line 15b, a drain electrode connected to the first power supply line 17, and a source electrode connected to the drain electrode of the driving TFT (DT). do.

Referring to FIG. 3 , the storage capacitor Cst is connected between the first node N1 and the second node N2 to maintain the gate-source voltage Vgs of the driving TFT DT for a predetermined time. .

In FIG. 3 , the OLED is emitted by the driving current generated by the driving TFT (DT), and the time during which the OLED emits light within one frame may be determined according to the turn-on holding time of the second switch TFT (ST2). At this time, the turn-on holding time of the second switch TFT (ST2) is determined according to the on duty (On Duty) of the emission signal (EM).

Each of these pixels PXL may be any one of a red pixel, a green pixel, a blue pixel, and a white pixel to implement various colors. A red pixel, a green pixel, a blue pixel, and a white pixel may constitute one unit pixel. A color implemented in a unit pixel may be determined according to emission ratios of a red pixel, a green pixel, a blue pixel, and a white pixel. A white pixel in a unit pixel may be omitted.

Referring to FIG. 1 , the panel drivers 12 and 13 write input image data DATA into the pixels PXL of the display panel 10 . The panel drivers 12 and 13 include a source driver 12 that drives the data lines 14 connected to the pixels PXL and a gate that drives the gate lines 15a and 15b connected to the pixels PXL. It includes a driver (13).

Referring to FIG. 1, the source driver 12 converts input image data DATA received from the timing controller 11 into an analog data voltage Vdata every frame, and converts the data voltage Vdata to the data lines. (14) is supplied. The input image data DATA may be image data before camera compensation or image data after camera compensation. The source driver 12 outputs an analog data voltage (Vdata) using a digital to analog converter (DAC) that converts the input image data (DATA) into a gamma compensation voltage.

A multiplexer may be further disposed between the source driver 12 and the data lines 14 of the display panel 10 . The multiplexer can reduce the number of output channels of the source driver 12 compared to the number of data lines by distributing the data voltage output through one output channel from the source driver 12 to a plurality of data lines. The multiplexer may be omitted depending on the resolution and purpose of the display device.

Referring to FIG. 1 , the gate driver 13 supplies the scan signal SCAN to the first gate lines 15a in a line sequential manner under the control of the timing controller 11 so that the data voltage Vdata is charged. Select horizontal pixel lines (L1 to Ln). Then, the gate driver 13 supplies the emission signal EM to the second gate lines 15b in a line sequential manner under the control of the timing controller 11, so that the horizontal pixel lines L1 to Ln emit OLED light. control the timing The gate driver 13 may be directly formed on the substrate of the display panel 10 together with the pixel array through a gate-driver in panel (GIP) process, but is not limited thereto. The gate driver 13 may be manufactured as an IC type and bonded to the display panel 10 through a conductive film.

Referring to FIG. 1 , the timing controller 11 receives digital data (DATA) of an input image and timing signals synchronized therewith from a host. The timing signals may include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock signal DCLK, and a data enable signal DE. The host may be any one of a TV (Television) system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, and a phone system.

The timing controller 11 includes a data timing control signal (DDC) for controlling the operation timing of the source driver 12 based on timing signals Vsync, Hsync, DE, and DCLK received from the host, and a gate driver 13 ) to generate a gate timing control signal (GDC) for controlling the operation timing.

The data timing control signal DDC includes a source start pulse, a source sampling clock, a source output enable signal, and the like. The source start pulse controls the sampling start timing of the source driver 12. The source sampling clock is a clock that shifts the data sampling timing. If the signal transmission interface between the timing controller 11 and the source driver 12 is a mini Low Voltage Differential Signaling (LVDS) interface, the source start pulse and the source sampling clock may be omitted.

The gate timing control signal GDC includes a gate start pulse, a gate shift clock, a gate output enable signal, and the like. In the case of a GIP circuit, a gate output enable signal (Gate Output Enable) may be omitted. A gate start pulse is generated at the beginning of each frame period and is input to the shift register of each gate driver 13 . The gate start pulse controls start timing at which the scan signal SCAN is output in every frame period. The gate shift clock is input to the shift register of the gate driver 13 to control the shift timing of the shift register.

The apparatus for compensating the image quality of a display device according to an embodiment of the present specification improves display stains caused by process deviation with camera compensation technology, and improves low-gradation display stains caused by drive characteristics with PWM (Pulse Width Modulation) driving method. . An apparatus for compensating a picture quality of a display device according to an embodiment of the present specification is a gamma curve including a white data voltage to be correlated with a PWM duty according to luminance in order to prevent deterioration of compensation performance of a camera when parallel to a PWM driving method. set the In this regard, it will be described by further connecting FIGS. 4 to 6 together with FIG. 1 .

4 is a diagram showing a method of controlling PWM duty according to an embodiment of the present specification. 5 is a diagram showing a gamma curve correlated with a PWM duty for each luminance region according to an embodiment of the present specification. And, FIG. 6 is a diagram showing a camera compensation method according to an embodiment of the present specification.

Referring to FIG. 1 , an apparatus for compensating a picture quality of a display device according to an exemplary embodiment of the present specification includes an optical compensator 30, a luminance measurement unit 40, and data so as to exhibit optimal compensation performance in improving display unevenness. Compensation unit 20 is included.

The optical compensator 30 sets a PWM (Pulse Width Modulation) duty for controlling OLED emission timing according to luminance, and sets a gamma curve to correlate with the PWM duty. The PWM duty means the on duty of the emission signal EM as shown in FIG. 4 . The OLED emission time is proportional to the on-duty of the emission signal EM. Therefore, the longer the PWM duty is set, the higher the display luminance.

As shown in FIG. 5 , the optical compensator 30 includes a first luminance region RB and RD in which the PWM duty varies and a second luminance region RA in which the PWM duty is fixed for the entire luminance region to set the PWM duty according to the luminance. RC) can be distinguished. The optical compensator 30 may increase the PWM duty in the first luminance region RB and RD in proportion to the luminance, and fix the PWM duty in the second luminance region RA and RC regardless of the change in luminance. Area RC may be omitted in the second luminance areas RA and RC. In this case, the first luminance regions RB and RD may be continuous. Since display unevenness due to driving characteristics is particularly problematic when expressing low grayscales, it is preferable that the first luminance regions RB and RD where the PWM duty is varied are set to have lower luminance than the second luminance region RA.

As shown in FIG. 5 , in order to set the gamma curve to be correlated with the PWM duty, the white data voltages are equally fixed in the first luminance regions RB and RD, and the white data voltages in the second luminance regions RA and RC are set. ), the white data voltage can be increased in proportion to the luminance. Here, the white data voltage indicates the highest gray voltage in the gamma curve. When the white data voltage is changed on the gamma curve, the data voltages of the remaining gradation sections are also changed accordingly.

The optical compensator 30 may express a desired luminance in the entire luminance range by setting the PWM duty and the white data voltage complementary to each other. The optical compensator 30 may express luminance of 0 to 60 nits and 100 to 300 nits by fixing the white data voltage and varying only the PWM duty in the first luminance regions RB and RD. On the other hand, the optical compensator 30 may express luminance of 60 to 100 nit and 300 to 650 nit by fixing the PWM duty and varying only the white data voltage in the second luminance regions RA and RC.

The optical compensator 30 may match white data voltages at boundary points (60 nit, 100 nit, and 300 nit points) of the first luminance region RB and RD and the second luminance region RA and RC, respectively. In this way, it is possible to prevent reversal of luminance according to gray levels and more easily express a desired luminance in the entire luminance range.

The luminance measurement unit 40 acquires a luminance profile for camera compensation by capturing an image reproduced on the display panel 10 based on the PWM duty and the gamma curve. In order to increase the accuracy of camera compensation, the luminance measurement unit 40 obtains a luminance profile only for the first luminance regions RB and RD to which the white data voltage is fixed. Camera compensation performance is affected by the size of the data voltage applied to the display panel. In order to exhibit the same compensation performance at different luminance points, the white data voltages corresponding to the luminance points must be the same. Optimum compensation performance can be obtained by setting the first luminance regions RB and RD as camera compensation regions, as in the exemplary embodiment of the present specification. This is because white data voltages for the luminance points are the same because luminance is expressed by PWM duty in the first luminance regions RB and RD. That is, since the same white data voltage is used in the first luminance regions RB and RD, the compensation voltage value calculated through camera compensation is also constant, so that compensation performance at various luminance points can be maintained at maximum.

The luminance measuring unit 40 may be implemented as a camera or a surface measuring unit, and may further include a measuring instrument driving unit. The meter driving unit may further increase the accuracy of the luminance profile by adjusting the photographing conditions (exposure time, etc.) of the luminance measurement unit 40 .

The data correction unit 20 analyzes the luminance profile obtained by the luminance measuring unit 40 to derive a compensation coefficient for improving the luminance deviation, and corrects the image data DATA based on the compensation coefficient. The data correction unit 20 corrects the image data DATA based on the compensation coefficient for the first luminance regions RB and RD corresponding to the camera compensation region.

In other words, the data correction unit 20 analyzes the gray level-luminance correlation for the luminance profile of the first luminance regions RB and RD as shown in FIG. spot the stain Display unevenness is due to process variation, etc., due to the difference in exposure amount in the photolithography process, the overlapping area between the gate and drain of the TFT, the height of the spacer, the parasitic capacitance between signal wires, and the parasitic capacitance between signal wires and pixel electrodes. This may be due to a difference from the normal display surface. Depending on the cause of the display stain, it may have a standard shape such as a dot, line, band, circle, polygon, etc., or an irregular shape.

The data compensating unit 20 derives a compensation value for eliminating display unevenness. This compensation value may be derived differently for each gray level. The data compensating unit 20 stores in a memory a location where display stains appear on the display panel 10 and a compensation value for each gradation to remove the display stains. Also, the data correction unit 20 corrects the input image data DATA based on the compensation values stored in the memory.

The data correction unit 20 may be built into the timing controller 11 or may be mounted on a separate circuit component and then connected to the timing controller 11 . The image data DATA corrected by the data correction unit 20 is written on the display panel 10 through the panel driving units 12 and 13 .

7 is a diagram illustrating a method for compensating a picture quality of a display device according to an embodiment of the present specification.

Referring to FIG. 7, in the method for compensating the image quality of the display device, optical compensation is performed by setting a PWM duty to control OLED emission timing according to luminance and setting a gamma curve to correlate with the PWM duty (S71, S72). ). That is, optical compensation is performed to implement desired gamma characteristics for each luminance according to the set PWM duty.

Next, in the method for compensating the picture quality of the display device, a luminance measurement step of obtaining a luminance profile by capturing a reproduced image based on the PWM duty and gamma curve in the display panel is performed (S73). That is, after the image before compensation is displayed on the display panel for camera compensation, a screen image is photographed by the luminance measuring unit.

Next, in the picture quality compensation method of the display device, a compensation coefficient for improving luminance deviation is derived by analyzing the luminance profile, and a data correction step of correcting image data based on the compensation coefficient is performed (S74 and S75). That is, the compensated data voltage is calculated and applied by applying a compensation coefficient to the corresponding data voltage according to the displayed screen.

8 is a diagram for explaining that compensation performance is improved when a method for compensating a picture quality of a display device according to an embodiment of the present specification is applied.

Referring to FIG. 8, when the image quality compensation method of this display device is applied, since the same white data voltage is set in the first luminance region RB, the white data voltage used at 100 nit luminance and 300 nit luminance are the same, so camera compensation Even at different luminance points, the same compensation performance can be implemented.

For example, if camera compensation is performed at 300 nit luminance, if the data voltage before compensation is 3.0V and the data voltage to be applied after compensation is 3.2V, 300 nit and 100 nit are only composed of PWM dimming, so even at 100 nit luminance, after compensation Set the data voltage to 3.2V. That is, the data voltage after compensation at 300 nit luminance can be used as it is even at 100 nit luminance. Therefore, if the white data voltage is fixed in the luminance region where camera compensation is performed and the luminance is expressed only by PWM dimming, camera compensation performance can be maintained the same in various luminances.

Through the above description, those skilled in the art will know that various changes and modifications are possible without departing from the technical spirit of the present specification. Therefore, the technical scope of the present specification is not limited to the contents described in the detailed description of the specification, but should be determined by the claims.

10: display panel 11: timing controller
12, 13: panel driving unit 20: data correction unit
30: optical compensation unit 40: luminance measurement unit

Claims (14)

a display panel including an OLED for each pixel;
an optical compensation unit that sets a PWM (Pulse Width Modulation) duty for controlling OLED emission timing according to luminance and sets a gamma curve to correlate with the PWM duty;
a luminance measurement unit acquiring a luminance profile by capturing an image reproduced from the display panel based on the PWM duty and the gamma curve;
a data correction unit that analyzes the luminance profile, derives a compensation coefficient for improving luminance deviation, and corrects image data based on the compensation coefficient; and
a panel driver to write the corrected image data on the display panel;
The optical compensation unit,
In order to set the PWM duty according to luminance, the entire luminance region is divided into a first luminance region and a second luminance region;
In the first luminance region, the PWM duty is increased in proportion to the luminance and the white data voltage is equally fixed;
In the second luminance region, the PWM duty is fixed regardless of luminance change and the white data voltage is increased in proportion to luminance;
The luminance measuring unit obtains the luminance profile for the first luminance region;
The data compensating unit corrects the image data for the first luminance region based on the compensation coefficient. delete delete According to claim 1,
The white data voltage indicates the highest gray level voltage in the gamma curve. According to claim 1,
The first luminance region has lower luminance than the second luminance region. According to claim 1,
The optical compensation unit,
An apparatus for matching the white data voltages at a boundary point between the first luminance region and the second luminance region so that luminance reversal according to the gray level does not occur. delete As a method for compensating the picture quality of a display device through a picture quality compensator,
an optical compensation step of driving the picture quality compensation device to set a PWM (Pulse Width Modulation) duty for controlling OLED emission timing according to luminance, and setting a gamma curve to correlate with the PWM duty;
a luminance measurement step of obtaining a luminance profile by driving the picture quality compensator and photographing a reproduced image based on the PWM duty and the gamma curve on the display panel of the display device;
a data correction step of driving the picture quality compensation device to analyze the luminance profile, deriving a compensation coefficient for improving luminance deviation, and correcting image data based on the compensation coefficient; and
and a panel driving step of driving the picture quality compensation device to write the corrected image data on the display panel,
The optical compensation step divides the entire luminance region into a first luminance region and a second luminance region in order to set the PWM duty according to luminance, increases the PWM duty in the first luminance region in proportion to the luminance, and fixing the same data voltage, fixing the PWM duty irrespective of luminance change in the second luminance region, and increasing the white data voltage in proportion to luminance;
The luminance measuring step includes obtaining the luminance profile for the first luminance region;
The data correcting step includes correcting the image data based on the compensation coefficient for the first luminance region. delete delete According to claim 8,
The white data voltage indicates a highest grayscale voltage in the gamma curve. According to claim 8,
The first luminance region has lower luminance than the second luminance region. According to claim 8,
The optical compensation step,
A method of matching the white data voltages at a boundary point between the first luminance region and the second luminance region so that luminance reversal according to the gray level does not occur. delete

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